Under the pay-as-you-go for pre-paid customers, the rate has been cut by 80 per cent to 2 paise per 10kb.

With reduction in tariffs, Vodafone also announced there will be no additional charges for roaming on data usage.

"Additionally, Vodafone will now allow its customers to use data from their bundle package while on-net roaming across any location in India without any additional charge," a company statement said.

Last month, Bharti Airtel, Idea Cellular and Reliance Communications had reduced tariffs for its third generation (3G) high speed internet services.

"With the introduction of these plans, we aim at establishing a foundation for providing a 3G data plan for everyone, making it affordable to the masses in the country," Vodafone India Chief Commercial Officer Sanjoy Mukerji said in a statement.

The 3G tariff war is happening at a time when most of the operators are up in arms against the high reserve price of spectrum proposed by sectoral regulators Trai. The government is likely to take a decision on spectrum price in the Empowered group of Ministers meeting on July 21.

The operators have warned that mobile bills could increase by up to 100 per cent in certain circles if the proposals are accepted.

According to industry experts, the price war in 3G tariffs may be an effort to cash huge investments made by telecom operators.

The government had received over Rs 67,000 crore from the 3G auctions held in 2010.

With operators taking huge loans to pay for the 3G licences, experts say operators are under pressure to recover the investment.